This invention relates to a novel and improved collapsible umbrella, and more particularly to a novel collapsible umbrella of the type having rib assemblies each of which comprises a main rib which is pivotally supported at one end thereof by a rib holder fixedly mounted on the top end of a shaft, a support rib which is pivotally supported at one end thereof by a runner slidably mounted on the shaft and to which the other end of the main rib is pivotally connected at an intermediate portion of the support rib, a roof rib which is pivotally supported at an intermediate portion thereof by the support rib at the other end of such support rib, and an auxiliary support rib which is pivotally connected at one end to an intermediate portion of the main rib and at the other end to one end of the roof rib, the rib assemblies being fashioned such that such assemblies are stretched and folded automatically when the runner is moved upwardly and downwardly on and along the shaft.
Collapsible umbrellas of this type are disclosed in, for example, U.S. Pat. Nos. 3,467,115; 3,672,381 and 3,693,642 and may be employed for use with a great convenience because ribs or rib assemblies are stretched or opened automatically when the umbrella is handled so as to open the same, whereas such ribs or rib assemblies are folded or closed automatically when the umbrella is handled so as to close the same. When a collapsible umbrella of this type is structured as a three-stage collapsible umbrella for the purpose of shortening folded or collapsed length of the umbrella, tip ribs are additionally provided which are pivotally connected at base ends thereof to the free ends of the roof ribs. While each of such tip ribs provides an extension of a roof rib when the umbrella is opened, such tip rib is folded alongside the roof rib when the umbrella is closed. In such three-stage collapsible umbrella, there are usually provided alongside the roof ribs elongated sliding means for stretching automatically the tip ribs when the umbrella is opened. Each of such elongated sliding means known per se from, for example, U.S. Pat. No. 3,457,931 is operatively connected at base end to the mentioned rib assembly and at the opposite end to the tip rib through a bent connecting means in a fashion such that the tip rib is stretched automatically, when the rib assembly is opened or stretched, by the pulling action of the sliding means which action is caused by the opening or stretching of the rib assembly.
Contrarily to a two-stage collapsible umbrella of the type mentioned, such three-stage collapsible umbrella according to the prior art causes an inconvenience that only the tip ribs provided for shortening the folded length of the umbrella are not folded or closed automatically when the umbrella is handled to close the same because the elongated sliding means provide no pushing action to the bent connecting means for folding the tip ribs. It is thus required in use that the tip ribs are manually folded one by one after the umbrella has been closed.
Accordingly, a primary object of the present invention is to provide a novel three-stage collapsible umbrella of the mentioned type in which tip ribs are also folded or closed automatically when the umbrella is handled to close the same.